The invention relates to a device for the coating of a substrate in a vacuum chamber. A substrate holder located in this vacuum chamber has at least one substrate location seat that can be moved by means of a driving motor from a loading station to a coating station in the vacuum chamber where an evaporation nozzle supplied with material in wire form is located.
It is known already to coat a small size compact disk of polycarbonate. Since it is very difficult to coat a polycarbonate disk having a diameter of approximately 300 mm (12 inches), this cannot be perfected with conventional sputtering technology. For this reason, the relatively large video disks for carrying optic and acoustic signals are made from PMMA (polymethylmethacrylate). The optic and acoustic information, after having been converted into digital form, is located in spiral arrangement of pits on the plastic medium and is read by a laser beam which is approximately 1 .mu.mm wide. The information is contained in the length and the depth of the pits. The indentations in the carrier material PMMA are covered on one side with a layer aluminum and an additional protective layer (lacquer). Double-sided video disks have the same design. In principle, they consist of two disks glued together.
The adhesiveness of the materials applied to the PMMA substrates during cathode sputtering, however, is not sufficient. The materials applied can easily be stripped off, which can lead to quality problems.
It is known to coat such video disks by means of so-called batch systems and/or one-chamber system that are to be operated on a discontinuous basis. However, these processes are complicated and expensive since they need to be loaded often and individually.